In the field of crown materials there is a rapid increase in the use of fine powders, particularly ceramic powders. In particular, the use of fine composite glass powders used as dental filler is increasing rapidly with the aging of society. In addition, the improvement of quality is becoming recognized as an important task as the use of these fine ceramic powders increases. Here “quality” refers the sintering characteristics, optical characteristics, and mechanical characteristics of the fine powder, and is determined by the size, shape and composition of the basic material. Accordingly, in order to improve the quality of fine powders, it is key to establish technologies for controlling the size, shape and composition of the fine powder. These fine glass powders are composed of comparatively low-cost ingredients, and high-value-added products can be made by increasing quality; the high-priced powder products currently on the market are seeing raising demand despite their non-spherical shape.
Currently, the manufacture of glass powders used as dental filler takes place by producing a fine powder form through a process of crushing after first melting the crown component glass with a suitable composition. The fine powders thus produced have a size typically of several μm, and because they have a sharp, non-spherical shape, their sintering and optical characteristics are problematically poor.